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Troubleshooting CRT monitor issues - ThinkPad and ThinkCentre

Select your symptom. If it does not appear in the following list, continue to the Need more help? section.

· Caring for your monitor
· No picture (screen is blank)
· Picture is scrambled
· Color is not uniform
· Screen image is not centered or sized properly
· Edges of the image are curved
· White lines show red or blue shadows at edges
· Picture is fuzzy
· Picture bounces or has wavy oscillations
· Picture is flickering
· Picture appears to be ghosting
· Wavy or elliptical (moire) pattern is visible
· COLOR RETURN function does not operate
· Two fine horizontal lines (wires) are visible
· Hum is heard right after the power is turned on
· ThinkVision C220p Monitors - Color degradation at the corners of the screen

Caring for your monitor

Symptom
Perform the following steps to fix the problem
Monitor is not clean

Be sure to disconnect the power cord from your monitor before you perform any maintenance on the monitor. Clean your monitor as follows:

  • Gently wipe the covers and the screen with a soft cloth, do not use solvents or abrasives.
  • Never drop water or other liquid into your monitor.
  • Remove finger marks and grease with a damp cloth and mild detergent.
  • Never use flammable cleaning materials to clean your monitor or any other electrical apparatus.
  • Do not rub, touch, or tap the surface of the screen with sharp or abrasive items such as a ballpoint pen or screwdriver. This type of contact may result in a scratched picture tube.
  • Do not use any type of cleaner containing an anti-static solution or similar additive as this may scratch the screen's coating.
  • Never apply detergent or other liquid directly to the screen. Dampen the cloth and then wipe.

No picture (screen is blank)

Symptom
Perform the following steps to fix the problem
Power indicator indicator is not lit
  1. Check that the power cord is properly connected.
  2. Check that the Power indicator (power) switch is in the "on" position.
"NO INPUT SIGNAL" message appears on the screen, or if the Power indicator (power) indicator is either orange or alternating between green and orange
  1. Check that the input switch setting is correct.
  2. Check that the video input connector's pins are not bent or pushed in.
  3. Check to see if the computer is in power saving mode. Try pressing any key on the computer keyboard or moving the mouse.
  4. Check that the computer's power is "on." Check that the video frequency range is within that specified for the monitor (Horizontal: 30-121 kHz, Vertical: 48-160 Hz)
  5. Check that the graphic board is completely seated in the proper bus slot.
"NO INPUT SIGNAL" and "CHECK SIGNAL CABLE" messages appear on the screen, or if the Power indicator (power) indicator is either orange or alternating between green and orange
  1. Check that the video signal cable is properly connected and all plugs are firmly seated in their sockets.
  2. Ensure that no pins are bent or pushed in the video input connector.
  3. Check that the input switch setting is correct.
  4. Check that the graphic board is completely seated in the proper bus slot.
"OUT OF SCAN RANGE" message appears on the screen Check that the video frequency range is within that specified for the monitor (Horizontal: 30-121 kHz, Vertical: 48-160 Hz).
No message is displayed and the Power indicatorindicator is green or flashing orange Refer to "Self-diagnosis function".

Picture is scrambled

  1. Check your graphics board manual for the proper monitor setting.
  2. Check the user's guide that comes with your monitorl and confirm that the graphics mode and the frequency you are trying to operate at is supported. Even if the frequency is within the proper range, some graphic boards may have a sync pulse that is too narrow for the monitor to sync correctly.
Color is not uniform

  1. Degauss the monitor. If you place equipment which generates a magnetic field, such as a loudspeaker, near the monitor, or you change the direction of the monitor, color may lose uniformity. The degauss function demagnetizes the metal frame of the CRT to obtain a neutral field for the uniform color reproduction. If a second degauss cycle is needed, allow a minimum interval of 20 minutes for the best result.
  2. Adjust the landing.
Screen image is not centered on sized properly

  1. Press the Auto size button to automatically size or center the picture.
  2. Adjust the size or centering.
    Note: Some video modes do not fill the screen to the edges. This problem tends to occur with certain graphic boards.
Edges of the image are curved

Adjust the geometry.

White lines show red or blue shadows at edges

Adjust the convergence.

Picture is fuzzy

  1. Adjust the contrast and brightness.
  2. Degauss the monitor.
    If you place equipment which generates a magnetic field, such as a loudspeaker, near the monitor, or you change the direction of the monitor, color may lose uniformity. The degauss function demagnetizes the metal frame of the CRT to obtain a neutral field for uniform color reproduction. If a second degauss cycle is needed, allow a minimum interval of 20 minutes for the best result.
  3. If red or blue shadows appear along the edges of images, adjust the convergence.
  4. If CANCEL MOIRE is ON, the picture may become fuzzy. Decrease the moire cancellation effect or set CANCEL MOIRE to OFF.
Picture bounces or has wavy oscillations

  1. Isolate and eliminate any potential sources of electric or magnetic fields. Common causes for this symptom are electric fans, fluorescent lighting, or laser printers.
  2. If you have another monitor close to this monitor, increase the distance between them to reduce the interference.
  3. Try plugging the monitor into a different AC outlet, preferably on a different circuit.
  4. Try the monitor on a different computer in a different room.
Picture is flickering


Set the refresh rate on the computer to obtain the best possible picture by referring to your computer's manual.

Picture appears to be ghosting


Eliminate the use of video cable extensions and/or video switch boxes if this symptom occurs. Excessive cable length or a weak connection can produce this symptom.

Wavy or elliptical (more) pattern is visible

Set CANCEL MOIRE to ON and adjust the degree of moire cancellation until the moire is at a minimum.

  1. Due to the relationship between resolution, monitor dot pitch and the pitch of some image patterns, certain screen backgrounds sometimes show moire. Change your desktop pattern.
COLOR RETURN function does not operate

  1. The monitor must be in normal operation mode (green power indicator on) for at least 30 minutes (for more information review using the COLOR RETURN).
  2. Adjust the computer's power saving settings to keep the monitor in normal operation mode for more than 30 minutes.
  3. The monitor may gradually lose its ability to perform this function due to the natural aging of the picture tube.
Two fine horizontal lines (wires) are visible

These wires stabilize the vertically striped aperture grille. This aperture grille allows more light to pass through to the screen giving the Trinitron CRT more color and brightness.

When viewing a white background, very thin horizontal lines may be visible on the screen as shown below. These lines are the shadows of the damper wires and are characteristic of CRTs that use aperture grilles. The wires are attached to the aperture grille on the inside of the Trinitron tube and prevent the vibration of the aperture grille.

Damper wires

Hum is heard right after the power is turned on


When the power is turned on, the auto-degauss cycle is activated. While the auto-degauss cycle is activated, a hum may be heard. The same hum is heard when the monitor is manually degaussed. This is not a malfunction.



  • Alias ID: MIGR-51436
  • Document ID: HT080231
  • Last Updated :17/06/2014
  • (c) 2014 Lenovo